I am continuing my quest for knowledge. I have just about finalized my method of building the elevated train layout, now I need to attach the roadbed to the top of the posts. My question is this, which is better for the roadbed? 5/4's X 6 Pressure Treated is cheaper than 2 X 6 Pressure Treated. How much of a span can I have with these two thicknesses of wood? I don't need it to support a 200 pound man, but I do want it to be stable. I am making the assumption on stability based on the fact that I expect that the 4 X 4 posts will not be moving. I have placed a 5/4 X 6 on the ground approximately 40" between supports and the movement up and down was minimal. It is my intention to use this lumber only on straight tracks. I will be using HDPE Stringers for the curves, and they will be supported every two feet. I am just trying to get a handle on my requirements (and expenses) for getting the first loop done
Honestly, I would use the more strong onf the choices. I'd go 2x6, as it would be stronger, and not flex as much. Also figure in warpage, shrinking, cupping, twisting, and other thngs that dimensional lumber encounters when exposed to the elements over time. My largest concern would be frost heave, followed by warping of the roadbed. A twist, or other warpage on even straight track would be a disaster. I would build this like a deck, like an elevated boardwalk. That means, the straightest materials you can find, plenty of wood sealer, and strong fasteners. Lag bolts, galvanized or stainless, and/or carriage bolts/nuts to secure things together. The kicker is you can jusify buying one of the cool Li-ion cordless tool kits. I'd spring for the Dewalt, but the Milwaukee is just as nice. A 12" heavy-duty miter saw is a must for this project.
Thank you for taking the time to reply. It is greatly appreciated. I will try to float the track on the base, rather than secure it, figure I can get away with that on straight sections, don't think that will be a good idea on the corved sections. Warping and cupping, any hints on how to prevent them? I'm hoping that I will have the frost heave taken care of. Thank you again.
Well, cupping and warping are tough to combat. I would start with (and I'm no expert, by any means) choosing the straightest stock you can get, or choose a recycled plastic product. Substandard stock can be used, but requires careful use, and you may end up fighting the warpage from the day you install it. This may mean visiting several lumberyards. Install the stock, and seal it immediately with a coat or 2 of a quality wood sealer. The less the wood has been exposed to the elements, the less it will cup or warp. I know a good woodworker and a construction fellow or 2 on this board, try PMing Pete Nolan, or SOO,MILW,CNW . I'd also ask the local lumber yard folks about this, see what they have to say,a nd get a couple opinions.
I would use the 2x6. I had some 5/4 on a deck and everyone warped and broke the nails. I used 2x6 cedar on my first railroad and they lasted 18 years, on the ground.
